Eighty-four-year-old comedian Dick Gregory has been hospitalized with a serious, but undisclosed, medical condition, according to his son Christian Gregory, who broke the news on Facebook.

Although Christian Gregory said that his father should be released “within the next few days,” he added: “When it comes to sickness and disease, one’s age is highly significant. There is no such thing as a ‘simple’ condition. In advanced age a simple cold or a simple infection could be catastrophic. At soon to be chronologically 85, my father’s true age far exceeds that. A life well-lived but heavily sacrificed has definitively taken its toll.”

The comedian was scheduled to perform, along with Paul Mooney, in Atlanta Wednesday, Aug. 16, but the show was postponed after he was hospitalized.

Dick Gregory was taken to the hospital after feeling ill Aug. 9 and was later released with instructions to rest for a few days, but his family returned him to the hospital three days later on Aug. 12, at which time he was admitted, according to his son’s Facebook post.

In his post, Christian Gregory thanked everyone for their prayers:

“I’ve watched my father for a lifetime heal the world,” the son wrote. “Today he is in need of your healing. We are truly grateful for the phenomenal care he has been receiving. My family and I remain thankful for all of the prayers, positive thoughts, messages and good energy.”